ABB RED615 Technical Manual page 790

Section 10
Power quality measurement functions
784
more than half of the nominal frequency period and less than one minute
(European Standard EN 50160 and IEEE Std 1159-1995).
These short-duration voltage variations are almost always caused by a fault
condition. Depending on where the fault is located, it can cause either a temporary
voltage rise (swell) or voltage drop (dip). A special case of voltage drop is the
complete loss of voltage (interruption).
PHQVVR is used for measuring short-duration voltage variations in distribution
networks. The power quality is evaluated in the voltage waveform by measuring
the voltage swells, dips and interruptions.
Voltage swell set
Voltage dip set
Voltage Int set
GUID-EF7957CE-E6EF-483E-A879-ABD003AC1AF9 V1 EN
Figure 422: Duration and voltage magnitude limits for swell, dip and
interruption measurement
Voltage dips disturb the sensitive equipment such as computers connected to the
power system and may result in the failure of the equipment. Voltage dips are
typically caused by faults occurring in the power distribution system. Typical
reasons for the faults are lightning strikes and tree contacts. In addition to fault
situations, the switching of heavy loads and starting of large motors also cause dips.
Voltage swells cause extra stress for the network components and the devices
connected to the power system. Voltage swells are typically caused by the earth
faults that occur in the power distribution system.
Voltage interruptions are typically associated with the switchgear operation related
to the occurrence and termination of short circuits. The operation of a circuit
breaker disconnects a part of the system from the source of energy. In the case of
overhead networks, automatic reclosing sequences are often applied to the circuit
V Var Dur point 1
min duration
magnitude
U_B
duration
1YHT530004D05 D
V Var Dur point 2
max duration
interruption
Technical Manual
swell
dip
615 series